Mud Run — Bill Swan

When Matt is too late to register for his new school's hockey team, he decides to join the cross-country running club instead.
At first it's every one for themselves -- no one runs with the pack, until finally a new coach demonstrates that tough competitors know the value of teamwork. When the championship finals arrive pouring rain makes the course a slippery mess, and forces the runners to make some hard choices.
Mud Run is a fast-paced, humorous story about team spirit and taking life one step at a time.